Polysilanes polymers

In this chapter, an introduction and overview of polysilane chemistry will be presented, concentrating on the linear high polymers (polysilanes) and their technological applications. Polysilane polymers were reviewed in 1986,(1) and a more general review of polysilane chemistry appeared in 1982.(2)... 

N Tanigaki, H Kyotani, M Wada, A Kaito, Y Yoshida, EM Han, K Abe, and K Yase, Oriented thin films of conjugated polymers polysilanes and polyphenylenes, Thin Solid Films, 331 229-238, 1998. 

Keywords Amplification Helix Optically active Polymer Polysilane... 

The long bonds in silicon-containing polymers can result in greater flexibility, relative to carbon-backbone polymers, as observed for PDMS. However, highly substituted all-silicon-backbone polymers (polysilanes) may be stiff despite the long Si-Si bond (2.35 A) because of large steric hindrance caused by two bulky groups on each backbone atom. 

Crystalline and amorphous silicons, which are currently investigated in the field of solid-state physics, are still considered as unrelated to polysilanes and related macromolecules, which are studied in the field of organosilicon chemistry. A new idea proposed in this chapter is that these materials are related and can be understood in terms of the dimensional hierarchy of silicon-backbone materials. The electronic structures of one-dimensional polymers (polysilanes) are discussed. The effects of side groups and conformations were calculated theoretically and are discussed in the light of such experimental data as UV absorption, photoluminescence, and UV photospectroscopy (UPS) measurements. Finally, future directions in the development of silicon-based polymers are indicated on the basis of some novel efforts to extend silicon-based polymers to high-dimensional polymers, one-dimensional superlattices, and metallic polymers with alternating double bonds. 

Damewood, J. R., Jr. West, R., Structure Calculations for Silane Polymers Polysilane and Poly(dimethylsilylene). Macromolecules 1985,18,159-164. 

In this chapter, a detailed description is given of these intriguing optical properties of certain polythiophene derivatives, and their analogy with chromic effects found in other 7r-conjugated (polydiacetylenes) and or-conju-gated polymers (polysilanes) is discussed. In order to explain these transitions, various molecular mechanisms are described. Finally, potential applications of these interesting optical effects are presented. 

Even though polysiloxanes are the most prominent class of silicon-containing polymers, polysilanes gained more and more interest within the last decades due to their interesting electrochemical and photophysical properties caused by the Si—Si backbone (2). Nevertheless, the synthesis of polysilanes is very sophisticated. The elaborated preparative procedures are not able to deliver polysilanes with high-molecular weight and narrow mass distributions, which is largely a consequence of the weak Si—Si bond. 

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